1945-1969: Southern Poland's Silesian region contains the largest deposit of brown coal in Europe. Under Soviet rule, Silesia is the center of coal mining and the coal-fired steel industry. The environmental consequences of such intense industrial activity in such a small geographic area are ignored.

1970-1989: Poland is one of Europe's most polluted countries. The heavily industrialized, highly populated area of Upper Silesia, which produces roughly 200 million tons of coal a year, is called the "Black Triangle." Severe acid rain all but destroys the area's mountain forests and acidifies the soil. Infant mortality, along with rates of cancer and other diseases, far exceed the national average.

1990-1997: Poland's dramatic shift to a market economy includes measures to curb runaway environmental pollution. Many aging factories are closed. A 1997 law creates a national energy policy. Poland invests in equipment to reduce industrial emissions. Levels of air and river pollutants drop significantly. Introduction of unleaded gasoline helps stem pollution from the growing number of cars.

1998-2003: Poland widens environmental regulations, upgrades monitoring equipment, and enacts fines for violators. Industrial air pollution decreases by as much as 50 percent. The Kyoto Protocol calls for Poland to reduce greenhouse gases 6 percent below 1988 levels by 2012. To comply, the country must reduce its reliance on dirty coal, find money to finance cleanup projects, and step up enforcement.